RESUMO
Green chemistry emphasizes the isolation of biologically active compounds from plants and biomass to produce renewable, bio-based products and materials through sustainability and circularity-driven innovation processes. In this work, we have investigated the extraction of rosmarinic acid (RA), a phenolic acid with several biological properties, from aromatic herbs using ultrasounds and low environmental risk natural deep eutectic solvents (NADES). Various solvent mixtures have been investigated, and the parameters influencing the process have been studied by a mixture-process experimental design to identify the optimal RA extraction conditions. The extraction yield has been calculated by HPLC-diode array analysis. The lactic acid:ethylene glycol mixture using an ultrasound-assisted process has been found to be the most versatile solvent system, giving RA yields 127-160% higher than hydroalcoholic extraction (70% ethanol). The deep eutectic solvent nature of lactic acid:ethylene glycol has been demonstrated for the first time by multi-technique characterization (1H-NMR and 13C-NMR, DSC, and W absorption properties). The aqueous raw extract has been directly incorporated into poly(vinyl alcohol) to obtain films with potential antibacterial properties for applications in the field of food and pharmaceutical packaging.
RESUMO
Polydimethylsiloxane (PDMS) polymers are extensively used in a wide range of research and industrial fields, due to their highly versatile chemical, physical, and biological properties. Besides the different two-dimensional PDMS formulations available, three-dimensional PDMS foams have attracted increased attention. However, as-prepared PDMS foams contain residual unreacted low molecular weight species that need to be removed in order to obtain a standard and chemically stable material for use as a scaffold for different decorating agents. We propose a cleaning procedure for PDMS foams obtained using a sugar templating process, based on the use of two different solvents (hexane and ethanol) as cleaning agents. Thermogravimetry coupled with Fourier Transform Infrared Spectroscopy (TG-FTIR) for the analysis of the evolved gasses was used to characterize the thermal stability and decomposition pathway of the PDMS foams, before and after the cleaning procedure. The results were compared with those obtained on non-porous PDMS bulk as a reference. Micro-CT microtomography and scanning electron microscopy (SEM) analyses were employed to study the morphology of the PDMS foam. The thermogravimetric analysis (TGA) revealed a different thermal behaviour and crosslinking pathway between bulk PDMS and porous PDMS foam, which was also influenced by the washing process. This information was not apparent from spectroscopic or morphological studies and it would be very useful for planning the use of such complex and very reactive systems.
RESUMO
Estudio prospectivo realizado en la Undidad de Medicina Familiar No. 47 de León, Guanajuato del Instituto Mexicano del Seguro Social, con 115 pacientes de hipertensos y 115 pacientes normotensos, con la finalidad de investigar el comportamiento de hiperlipidemia entre ambos grupos. Se elaboraron los exámenes de colesterol y triglicéridos utilizando el analizador de química clínica 550 express, así como la prueba de colesterol -HDL (High Density Lipoproteins) (técnica manual). La prevalencia de hiperlipidemia es mayor en los pacientes hipertensos en número y porcentaje estadísticamente significativos en comparación con los normotensos y el riesgo de cardiopatía coronaria aumenta en esos sujetos a medida que asciende su colesterol sanguíneo, aunado al aumento de LDL (Low Density Lipoproteins). Sin embargo, el estudio reportó que entre los normotensos también se encuentran cifras altas de colesterol y/o triglicéridos, por lo que es conveniente realizar estos estudios periódicamente